Slow-burning black-powder composition



reamed Dec. i2, 1922.

.1osr.rn r'naer GRAY,

or NEWPORT, DELAWARE,

PATENT; orrics. I

ASSIGNOR TO E. I. DU PONT DE NEMOURS & COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE.

SLOW-BURNING BLACK-POWDER COMPOSITION.

and controlling the burning speed of .the powder. a The princi al object of my invention is 16. to produce a lack powder composition that by reason of its re atively'slow and at the same time uniform rate of burning is especially suitable for use in artillery time fuses,

military fuses for bombs, grenades, etc.,and 20 for use in blasting tape fuses,*squibigniters, etc. P

Black powder as heretofore manufactured, either for blasting, fire arms, fuse or ignition purposes has consisted of a mixture of'ap- 25 proximately 7 potassium nitrate, 10% sulphur, charcoal.

In powder intended for blasting purposes the potassium nitrate, commonly called saltpetre, has been largely replaced by. sodium nitrate but for the other uses mentioned the composition containing potassium nitrate is largely used on account of its lesser hygroscopicity as compared with the composition containin sodium nitrate.

The speed 0 combustion of powder of the above com osition' is influenced by quality 40 of charcoa andother ingredients, uniformity of incorporation of ingredients, ranulation and specific gravit of finishe powders, and by many other actors.

speed of combustionof the powder may be 45, varied within certain imits y varying the above-mentioned factors, for many purposes especially for use in fuses and 1 iters,.it, is necessary to have a black ow er which will burn at a slower rate an 60 time ata more uniform rate of combustion than givendoy the usual black powder.

Heretofore, these requirements for ablack ever, black powder be illustrated While theat the same'.

m9. Serial a... 288,135.

powder have been met bychan ing the proportions of charcoal and sulp 1111'. By increasin the percentage. of sulphur and correspomingly decreasing the percentage of charcoal the speed of combustion of the powder can be very materially reduced. Howof this composition leaves upon combustion excessive amountsof residue which is very objectionable and renders the powder unfit for many purposes, espeeially foruse in military fuses such as artillery time fuses; Another important objectionisthat the burning speed of the pow-,

der cannot be"reduced to the extent desired for many purposes by varying the proportions of the ingredients potassium orvsodium nitrate, sul bar and charcoal.

I have discovered that the burning speed of black powder may be retarded by the addition of rosin as an ingredient, the reduction in s eed of combustion depending approximate y on the amount of rosin present in thepowder.

This new black powder containing rosin has many the slow-burning powder obtained by varying the proportions of the in redients potassium or sodium nitrate, sulp iur and charcoal, the advantages of most importance being greater .ease of. ignition, greater uniformity of burning at reduced speeds of combustion, tion. y

The composition of my new'powder may by the. following example:

72.8% sodium or potassium nitrate,

9.7% sulphur,

14.5 charcoal,

3.0% rosin,

The proportions of alkali-metal nitrate, as well as sulphur and charcoal in the powder, which are to be substituted in art by rosin, may portions 5% of nitrate, 10% of sulphur advantages over vary considerably from t epro-- and less residue upon combus- 7 2.0 parts potassium nitrate, 11.2 parts sulphur, 16.8 parts charcoal,

3.0 parts rosin,

will give a powder with reduced burning speed which makes it particularly suitable for use in slow-burning -second artillery time fuse. Powder made on the above formula, with omission of the rosin, will give a burning time of about 28 seconds in this same 15-second artillery time fuse.

I have found that whereas black powder of the following composition:

72.0 parts potassium nitrate, 11.2 parts sulphur, 16.8 parts charcoal,

double tape fuse at the rate per foot of fuse, the addition of parts of rosin reduces the rate of burning, and when 11 parts of rosin are added to the above composition will burn in of 15 seconds one or more I the time of burning of the double tape blasting fuse is increased ,to about 300 seconds per foot. Although in the above examples the proportion of rosin has ranged from about 2 to 12 parts for 75 parts of alkali-metal nitrate, a larger or smaller amount may be used depending upon pars, ticular requirements. The increase in time of'burning is approximately directly proportional to the amount of rosin added to the particular black powder composition.

I have also found that the use of rosin as an ingredient of black powder does not necessitate any change in the usual method of manufacture. I have further found that the rosin may be added at different stages during the manufacture of the black powder with the same result. For example, the entire amount ofrosin may be added to the charcoal and sulphur when these ingredients are being pulverized preliminary to being mixed or incorporated with the potassium nitrate in the wheel mill. Or the rosin may be added during the incorporation of the pulverized charcoal-sulphur mass and the potassium nitrate in the wheel mill. Or in the case of the manufacture of meal powder the rosin may be added to the dried black powder composition, after removal from the wheel mills and subsequent drying, at the time the composition is being mealed, i. e., being pulverized to produce t-heso-called meal powder.

The rosin which I use may be any of the several grades of rosin obtained by the distillation of turpentine oil from crude turpentine. I have found that the water white grade of rosin gives excellent results but I do not limit myself'to this grade as some of the other grades are also suitable.

ile I prefer to use the resin which is commonly known obtained from turpentine oil, many other resins are likewise suitable for my purpose,

provided they are hard and brittle and can be very finely pulverized. The amount of the different resins required will differ ac cording to the chemical composition of the particular resin.

While I detail, I wish-it to be understood that many changes maybe made therein without departing from the spirit and scope thereof.

claim:

1. A black powder composition comprising an alkali-metal nitrate, sulphur, charcoal, and rosin, and having a burning-speed substantially less than that of a corresponding powder composed of alkali-metal nitrate, sulphur and charcoal.

fuse powder comprising an alkalimetal nitrate, sulphur, charcoal, and from about 2 to 12 parts of rosin for each 75 parts of nitrate, and having a burning-speed substantially less than that of a corresponding powder composed of nitrate, sulphur, and charcoal.

3. A fuse powder comprising potassium nltrate, sulphur, charcoal, and a finely pulveriza'ble resin, and having a burning-speed substantially less than that of a corresponding powder composed of nitrate, sulphur, and charcoal. I

4. A slow-burning black powder composition comprising from about 72 to 75 parts of potassium nitrate, from about 7 to 12 parts of sulphur, from about 14: to 17 parts of charcoal, and from about 2 to 12 parts of a finely pulverizable resin.

A slow-burning black powder composition comprising from about 72 to 75 parts of potassium nitrate, fromabout 7 to 12 from about 14 to 17 parts JOSEPH PERCY GRAY.

have described my invent-ion in r 

